linux-kernel - [PATCH v4 5/8] arm64: Define TIF_POLLING

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Date: Thu, 15 Feb 2024 09:41:47 +0200
From: Mihai Carabas <mihai.carabas@...cle.com>
To: linux-arm-kernel@...ts.infradead.org
Cc: kvm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, catalin.marinas@....com, will@...nel.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com, pbonzini@...hat.com, wanpengli@...cent.com,
        vkuznets@...hat.com, rafael@...nel.org, daniel.lezcano@...aro.org,
        akpm@...ux-foundation.org, pmladek@...e.com, peterz@...radead.org,
        dianders@...omium.org, npiggin@...il.com, rick.p.edgecombe@...el.com,
        joao.m.martins@...cle.com, juerg.haefliger@...onical.com,
        mic@...ikod.net, mihai.carabas@...cle.com, arnd@...db.de,
        ankur.a.arora@...cle.com
Subject: [PATCH v4 5/8] arm64: Define TIF_POLLING_NRFLAG

From: Joao Martins <joao.m.martins@...cle.com>

The default idle method for arm64 is WFI and it therefore
unconditionally requires the reschedule interrupt when idle.

Commit 842514849a61 ("arm64: Remove TIF_POLLING_NRFLAG") had
reverted it because WFI was the only idle method. ARM64 support
for haltpoll means that poll_idle() polls for TIF_POLLING_NRFLAG,
so define on arm64 *only if* haltpoll is built, using the same bit.

Signed-off-by: Joao Martins <joao.m.martins@...cle.com>
Signed-off-by: Mihai Carabas <mihai.carabas@...cle.com>
---
 arch/arm64/include/asm/thread_info.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index e72a3bf9e563..72273a2168fa 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -69,6 +69,9 @@ struct thread_info {
 #define TIF_SYSCALL_TRACEPOINT	10	/* syscall tracepoint for ftrace */
 #define TIF_SECCOMP		11	/* syscall secure computing */
 #define TIF_SYSCALL_EMU		12	/* syscall emulation active */
+#if IS_ENABLED(CONFIG_HALTPOLL_CPUIDLE) || IS_ENABLED(CONFIG_HALTPOLL_CPUIDLE_MODULE)
+#define TIF_POLLING_NRFLAG      16      /* poll_idle() polls TIF_NEED_RESCHED */
+#endif
 #define TIF_MEMDIE		18	/* is terminating due to OOM killer */
 #define TIF_FREEZE		19
 #define TIF_RESTORE_SIGMASK	20
@@ -91,6 +94,9 @@ struct thread_info {
 #define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)
 #define _TIF_SECCOMP		(1 << TIF_SECCOMP)
 #define _TIF_SYSCALL_EMU	(1 << TIF_SYSCALL_EMU)
+#if IS_ENABLED(CONFIG_HALTPOLL_CPUIDLE) || IS_ENABLED(CONFIG_HALTPOLL_CPUIDLE_MODULE)
+#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
+#endif
 #define _TIF_UPROBE		(1 << TIF_UPROBE)
 #define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
 #define _TIF_32BIT		(1 << TIF_32BIT)
-- 
1.8.3.1